An actual coverage area of a cell is determined by various factors, including a carrier frequency, receiver performance of a terminal, and the like. During cell planning, on one hand, a carrier frequency is taken into consideration; on the other hand, a network is deployed in combination with a channel environment and receiver performance of a terminal. For example, on a built network or a network prepared and planned to be built, large-scale fading features of a majority of user terminals are similar, and in this case, the majority of terminals can be served within a transmission distance range of a carrier, that is, a cell can cover a distance within which these terminals are located. However, if there are a minority of terminals also within the distance in the coverage area of the cell, but a fading feature differs relatively greatly from that of the majority of terminals, receive power of a signal upon arrival at these terminals is particularly small, and these terminals cannot implement communication under sensitivity of receivers. For example, a terminal located in a basement has a signal receiving energy or power that is 10 dB to 20 dB less than that of a terminal located on the ground. How to ensure that these terminals located within a physical coverage area of a cell can still implement normal communication with a base station in a case of severe signal fading caused by an external factor is our current research topic.
A current research status of the topic is that a coverage enhancement technology is used for these terminals that are located in a severe fading environment, so that these terminals work in a coverage enhancement mode. In broad terms, in the used coverage enhancement technology, data is repeatedly transmitted within multiple transmission time intervals (TTI), and a receiver can receive and combine multiple copies, thereby improving detection performance. Certainly, how to configure a physical random access channel (PRACH) resource for user equipment that works in a coverage enhancement mode urgently needs to be resolved.